Ravaged by heat and a lack of repairs and funding, almost 1,000 dams in Chongqing face collapse if hit by heavy downpours forecast for the coming weeks, the city's government has warned.

The 937 reservoirs, of which about 300 have dried up, had cracked after two months of scorching heat, with some cracks as deep as 1 metre, according to a notice on the Chongqing Water Resources Bureau's website.

Chongqing has been hit by the worst drought in 50 years, with temperatures topping 45.5 degrees Celsius on August 16 - the highest recorded in 55 years. Two-thirds of local rivers and lakes have dried up.

The disaster has caused losses of 3.8 billion yuan and left 7.8 million people facing shortages of drinking water in Chongqing, the country's worst-affected area, according to the latest official figures.

The bureau said the municipality had identified 937 hazardous dams - more than one-third of its 2,786 reservoirs - with varying degrees of cracks even before the drought set in.

With weather forecasters predicting downpours next month, the cracks could lead to landslides and collapses, the bureau said.

Xinhua reported that the poor condition of the dams should be blamed on a lack of repairs and funding. The central government had identified 195 of the 937 barriers as national projects for which the State Council would pay two-thirds of the 1.5 billion yuan repair cost. However, the repair work was hindered by the Chongqing government's failure to raise funds for the remaining one-third, with the authorities reaching only 24 per cent of their target.

Still, Chongqing's problem is only the tip of the iceberg.

On August 7, Vice-Minister for Water Resources E Jingping told mainland media that more than one-third of the 85,000 dams across the country suffered from similar problems.

'[Since] I have taken up this job, the biggest worry for me is the safety of reservoirs. Please, please don't let them collapse,' Mr E was quoted by state media as saying.

Mr E, who is also the secretary-general of the National Flood Control and Drought Relief Headquarters, said he lost sleep every July and August, a period which has seen disasters for the past 14 years.

Fan Xiao , a Sichuan-based geologist, said China not only had the most and the biggest dams in the world, but also the most dangerous.

'Whether there are droughts and flooding or not, the situation is critical and the central government should take action,' he said.

Ma Jun , director of the Beijing-based Institute of Public and Environmental Affairs, said other departments should co-operate with the Ministry of Water Resources. He said the government could not justify investing in mammoth dams like the Three Gorges project while ignoring the ministry's repeated warnings of the dangers posed by older dams.